Tadayoshi Kisaragi (更衣唯芳) is the father of Saya and the priest of the shrine in which they reside.
He is very wise and thoughtful. He cares for Saya greatly and helps her with her training and is seen promptly commenting on Saya's clumsiness. He is known to try and hide the fact that he likes sweets to look cool in front of Saya as stated by Fumito.
Whilst in his monstrous state, he becomes an almost emotionless monster and goes berserk with nothing but murderous intent.
He is a middle-aged man with dingy pale skin. He has short black hair that is kept up with a white hairpiece that looks a lot like a bow and dark-ish brown eyes. He wears traditional black and white Japanese clothing which includes a white coat with bells on the bottom of it.
He is first seen interrupting Saya when she was trying to find out more about the 'light' she's been seeing recently. After that, she runs towards him but falls on her face and he tells Saya that she shouldn't fall on her face all the time. Soon after he asks her if she saw the 'light' again and she says yes. He asks her if she was able to grasp it but Saya says that when she reaches her hand out to it, it always escapes. Saya states that she thinks she remembers it from somewhere but she wasn't sure and Tadayoshi tells her that her mom was also a shrine maiden and she too saw auguries from the real world and the dream world. He then goes on to tell her the 'light' she has been seeing may be an omen of the future and Saya added that it may help her to fulfill her duty. He asks her to tell him anything she finds out about it and reminds her that she should get dressed to go and eat breakfast next door but Saya runs and falls again.Later on, when Saya arrives home he tells her to come to the main shrine. There he tells her that the Eight Trigrams has revealed that an Elder Bairn will appear tonight and gives her the sacred sword telling her to slay it. After she defeats it, she makes her way back to the shrine where Tadayoshi is seen waiting for her. She says that she slew the Elder Bairn and he tells her they need to purify the sacred blade but notices her hand shaking. He tells her that she was probably just holding the sword too tight and takes it from her. Tadayoshi then says that he heated some water so she should take a bath and together they walk back to the shrine.
The next time he is seen is when Saya comes back from school the next day and hears her singing about him (and is seen blushing at this). They both go to the archives where Tadayoshi tells her that he looked to do some research on who named the creatures Elder Bairns but found nothing. He states that even though they don't know who named them, it is certain that they have fed on men for a long time and that the only thing that can defeat them is the sacred blade.Tadayoshi then continues, saying that Saya's mother also fought against the Elder Bairns but fell to them. Saya then tells him she will not fail and that she will protect him and everyone else and goes off to fight it.The next day he is seen watching Saya make some Tamagoyaki for him with Fumito. Saya smushes the end of the Tamagoyaki but Tadayoshi says he'll eat it still eat it. After they were done eating, he said the Tamagoyaki was good and Saya says she'll try harder next time. Fumito gives Saya her coffee and she asks where her father's coffee was and he said he just put it on. When Saya says that she'll make her father drink her's instead but Fumito said that Tadayoshi can only drink really weak coffee and Tadayoshi looks away (probably embarrassed). Fumito then gives Saya more Guimauves and asked Tadayoshi if he wanted one too but he said that he'll pass. Later on, in the evening, he tells Saya that an Elder Bairn was going to appear but it didn't appear on the Eight Trigrams. He also stated that it may be different than the others she's seen before and tells her to go defeat it. In the last episode we learn that Tadayoshi is a half human/half Elder Brain and that he was born after the convenent between the two species was made. After killing Kanako by drinking her blood and beheading her (due to being awakened by Saya's blood), he attacks Saya following Funimoto's orders. After being beaten, he told Saya his real feelings for her before dying.
He is mentioned and has a small cameo in the movie The Last Dark.
He cares for Saya greatly and helps her with her training. She thinks that he is cool and she loves him very much. And apparently (according to Fumito) he likes to act cool in front of her to avoid further embarrassment. They deeply care about each other and share a strong bond. When later he is shown to be an Elder Bairn he is unable to kill her. After his defeat, he tells Saya that even though it was just an act (that they were never blood-related), he still loved her as though she really was his daughter, and he was "happy to be with someone like her".
Tadayoshi and Fumito have known each other for a long time and know each other very well. However. it was never told how they first met other than they've known each other since high school.